After being presumed dead, the Halliwell sisters begin their demon-free existence with new identities: Phoebe is overwhelmed with visions of her future husband; Paige begins hearing her whitelighter call, which draws her to a mysterious young witch; Piper attempts to deal with her financial situation, the club and her children. Meanwhile, a brash young demon decides that he wants the Halliwell manor as a trophy and plots to kill Victor to get to it.
While attempting to take over the Underworld, a young demon plots to lure the Charmed Ones out of hiding, but when Billie stumbles onto his plot ,she becomes one of his victims instead.
When Piper goes for a job interview with a corporate recruiter, she's shocked to learn that the background check of her assumed identity was that of a woman wanted for murder. Meanwhile, Phoebe has a premonition of Dex being in an earthquake.
Wyatt's school play brings out the competitive nature in Piper when her hand-sewn costume & parenting abilities are criticized by another mother. However things go from bad to worse, because this Stepford-like mother is actually a demon in disguise bent on kidnapping Wyatt in a plot to resurrect the Source. Meanwhile, Paige spies Dex with another woman, and despite Phoebe's objections, butts in.
Billie jeopardizes the Charmed Ones' new lives when Agent Murphy spots her using her powers to save an innocent. Meanwhile, Phoebe's overnight trip with Dex comes to a surprising conclusion when Billie casts a spell to make her happy, a spell with unexpected consequences.
Billie must deal with her painful childhood memories of her sister's kidnapping, before she can vanquish her latest demon target, The Dogan. Meanwhile, the press are bombarding the sisters, since the announcement of their teaming with Homeland Security, so Paige goes to the Elders for help.
Wanting to return to her old career as a social worker, Paige's plans get put on hold, when her Whitelighter father, Sam, returns asking for her help with his charge. Meanwhile, Piper and Leo go to see a magical marriage counselor who thinks the best therapy is for them to walk a mile in each others' shoes - literally.
Agent Murphy gives the sisters their first Homeland Security case - searching through cold case files, where Phoebe and Billie discover a belt that gives Billie superpowers. Meanwhile, Piper and Leo are on the hunt for a band to play at P3; and Paige meets a handsome man, who happens to be her new charge's parole officer.
When a demon escapes from custody, Agent Murphy enlists the Charmed Ones to help, where they learn a government created virus is spreading amongst magical beings, that causes them to "hulk out". Meanwhile, Billie becomes infected with the virus and it's up to the sisters to find an antidote.
The Angel of Death returns to visit the Charmed Ones but they're shocked to learn that he's there for Leo. To try to stop him from taking Leo, Piper casts a spell that backfires, making every man a Leo lookalike, forcing Piper to take drastic measures and ask the Elders and the Avatars for help. Meanwhile, Billie continues her search for the truth behind her sister's disappearance.
When her parents come for a visit, Billie accidently transforms them into assassins and also manages to contact a demon who is posing as a human. Meanwhile, Piper attempts to continue her life without Leo; Paige tries to make a connection with Henry; Phoebe tries to find a way to have her own life.
With the intention of helping his parolee get a loan, Henry, along with Paige, go to a bank but instead the parolee decides to take everyone at the bank hostage. Meanwhile, Phoebe and Piper have their hands full when, during his third birthday party, Wyatt turns three of his toys into real people.
Phoebe, in an attempt to move on with her own life, signs a lease for a new apartment, and Paige considers moving in with Henry. However the sisters are forced to remain under the same roof when a demon shrinks them and traps them in a replica dollhouse of the Manor.
During Chinese New Year, a demon attempts to steal a mystical wooden staff, that's protected by the Zodiacs and they enlist the aid of Piper. Meanwhile, Phoebe enjoys her new place by throwing a housewarming party that gets out of control; a monk teaches Billie how to use her power of projection to find her sister; Paige tries to get through to Henry about her magical abilities.
Paige learns the difficulties of dating a mortal when Henry becomes too involved in the magical world and is torn when another suitor arrives hoping to convince her to marry him so they can become the ultimate magical couple. Meanwhile, Billie finally finds her missing sister, Christy; Piper faces a romantic decision when she runs into an old flame and begins to wonder if she should move on with her life.
Piper organizes an engagement party for Paige and Henry, but the couple begin to get cold feet. Meanwhile, Phoebe discovers a strange man following her but soon learns he is actually Cupid; a demon kidnaps Christy in order to get to the Charmed Ones.
After Paige and Henry leave for their honeymoon, Cupid "Coop" takes Phoebe on a journey through her past romances in an attempt to revive her excitement for love. Meanwhile, a group of magical teens, who are protégés of Leo, come to the manor seeking refuge from demons that have overtaken the Magic School, forcing Piper to take charge. Billie and Christy's parents come to town for a visit, but Christy refuses to see them in order to test Billie.
Coop comes to the conclusion that he has fallen for Phoebe but she'd rather spend her life with a mortal. Meanwhile, Piper is on the hunt for killer demons; Paige finds it hard balancing life as a Charmed One with that of a married woman.
Piper and Phoebe devise a plan to recover Leo. Meanwhile, Paige rescues her new charge from a Darklighter; Billie is forced to make an important decision.
In an attempt to destroy the reputation of the Charmed Ones, Billie & Christy resort to trying to make the magical community see that the Halliwells only care about themselves. Meanwhile, Phoebe begins to lust after Coop; Paige cannot hear her charges' call for help; Piper becomes the perfect 1950s housewife.
Forced to hide from Billie and Christy, the Charmed Ones find themselves stuck in the Underworld. Meanwhile, Leo appears to Piper and offers demonic approval; Coop searches for Phoebe; Billie & Christy resort to summoning the Hollow to stop the Charmed Ones and the Charmed Ones do the same.
Piper & Leo, with help from Coop's ring, must travel back in time to change the events that lead to the deaths of Piper's sisters. Meanwhile, Billie uses her power of Projection to do the same thing; many familiar faces gather to help Piper in her time of need.